[chore] update dependencies (#4386)

- codeberg.org/gruf/go-bytesize v1.0.3 -> v1.0.4
- codeberg.org/gruf/go-kv/v2 v2.0.6 -> v2.0.7
- codeberg.org/gruf/go-mutexes v1.5.2 -> v1.5.3
- codeberg.org/gruf/go-structr v0.9.7 -> v0.9.8
- codeberg.org/gruf/go-ffmpreg v0.6.8 -> v0.6.9
- github.com/tomnomnom/linkheader HEAD@2018 -> HEAD@2025

all of the above codeberg.org/gruf updates are in preparation for Go1.25, except for bytesize, and also ffmpreg which is a rebuild with the latest version of ffmpeg (v5.1.7)

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4386
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

vendor/codeberg.org/gruf/go-structr/key.go

@@ -4,6 +4,7 @@ import (
 	"sync"
 
 	"codeberg.org/gruf/go-byteutil"
+	"codeberg.org/gruf/go-mangler/v2"
 )
 
 // Key represents one key to
@@ -14,6 +15,37 @@ type Key struct {
 	raw []any
 }
 
+// MakeKey generates Key{} from given parts.
+func MakeKey(parts ...any) Key {
+	buf := new_buffer()
+	buf.B = mangler.AppendMulti(buf.B[:0], parts...)
+	key := string(buf.B)
+	free_buffer(buf)
+	return Key{
+		raw: parts,
+		key: key,
+	}
+}
+
+// MakeKeys generates []Key{} from given (multiple) parts.
+func MakeKeys(parts ...[]any) []Key {
+	keys := make([]Key, len(parts))
+	if len(keys) != len(parts) {
+		panic(assert("BCE"))
+	}
+	buf := new_buffer()
+	for x, parts := range parts {
+		buf.B = mangler.AppendMulti(buf.B[:0], parts...)
+		key := string(buf.B)
+		keys[x] = Key{
+			raw: parts,
+			key: key,
+		}
+	}
+	free_buffer(buf)
+	return keys
+}
+
 // Key returns the underlying cache key string.
 // NOTE: this will not be log output friendly.
 func (k Key) Key() string {
@@ -31,11 +63,6 @@ func (k Key) Values() []any {
 	return k.raw
 }
 
-// Zero indicates a zero value key.
-func (k Key) Zero() bool {
-	return (k.key == "")
-}
-
 var buf_pool sync.Pool
 
 // new_buffer returns a new initialized byte buffer.